栅格翼水下空化特性数值仿真研究

Numerical Research on Underwater Cavitation Characteristics of Grid Fins

为探索水下应用典型栅格翼构型的空化特性,该文建立了基于全空化模型及Mixture多相流模型的数值仿真方法。在栅格翼水下流场特性试验结果的基础上验证了数值计算模型的正确性及适用性,并以此开展不同来流空化数下的栅格翼流场仿真计算。通过对复杂翼面特征区域内的多相流动流场结构分析,获得了不同空化数下栅格翼设计构型的流体动力参数变化规律及空泡演化特征。结果表明,初生空化始于栅格翼边框外缘及翼片交叉处,并随空化数降低在翼面上逐渐形成空泡。当空化数降低至0.40~0.45之间时,翼面上的空泡形态在翼片背部逐渐闭合并形成最终的单一空泡形态,此空化数可作为泡型的转化临界空化数。随着来流攻角的不断增加,翼面两侧的压差逐渐增加,背流面的压力进一步减小,促进了空化现象的进一步发展。

In this paper,a simulation model is established to calculate the cavitation characteristics of the underwater grid fins by coupling the full cavitation model into the N-S equation.With the experimental results conducted in a water tunnel,the simulation model is verified.Then the cavitation characteristics of the underwater grid fins are investigated by simulating the flow with different cavitation numbers and attack angels.The results show that the cavitation is firstly noticed at the crossing between the outer edge of the frame and the fins.At the higher cavitation number,local sheet-cavity are found on the fins.With the decrease of the cavitation number,the sheet-cavity would transfer the super-cavity gradually.The critical cavitation number is range of 0.40~0.45.The increase of the attack angels would raise the pressure difference between the upper and lower surfaces of the fins.This would promote the development of the cavitation.